Refactor display_info_provider_chrmoeos and provide standard impl for other

platforms.

Added gfx::Screen::GetAllDisplays()

I moved QueryInfo on Windows to UI thread as this gfx::Screen is already
querying this info on UI thread, and supposed to be fast.

Next Step:
 Implement GetAllDisplays for win/mac/gtk.

BUG=122863
R=hongbo.min@intel.com, sky@chromium.org

Review URL: https://codereview.chromium.org/23205029

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@219293 0039d316-1c4b-4281-b951-d872f2087c98

19 files changed, 182 insertions, 111 deletions

diff --git a/ash/display/display_manager.h b/ash/display/display_manager.h
index b2ef8d1..4699eee 100644
--- a/ash/display/display_manager.h
+++ b/ash/display/display_manager.h
@@ -181,6 +181,8 @@ class ASH_EXPORT DisplayManager
   // when displays are mirrored.
   size_t GetNumDisplays() const;
 
+  const std::vector<gfx::Display>& displays() const { return displays_; }
+
   // Returns the number of connected displays. This returns 2
   // when displays are mirrored.
   size_t num_connected_displays() const { return num_connected_displays_; }
diff --git a/ash/screen_ash.cc b/ash/screen_ash.cc
index f2217d7..4ba2868 100644
--- a/ash/screen_ash.cc
+++ b/ash/screen_ash.cc
@@ -123,10 +123,14 @@ gfx::NativeWindow ScreenAsh::GetWindowAtCursorScreenPoint() {
   return wm::GetRootWindowAt(point)->GetTopWindowContainingPoint(point);
 }
 
-int ScreenAsh::GetNumDisplays() {
+int ScreenAsh::GetNumDisplays() const {
   return DisplayController::GetNumDisplays();
 }
 
+std::vector<gfx::Display> ScreenAsh::GetAllDisplays() const {
+  return GetDisplayManager()->displays();
+}
+
 gfx::Display ScreenAsh::GetDisplayNearestWindow(gfx::NativeView window) const {
   return GetDisplayController()->GetDisplayNearestWindow(window);
 }
diff --git a/ash/screen_ash.h b/ash/screen_ash.h
index 649c3d9..95869b0 100644
--- a/ash/screen_ash.h
+++ b/ash/screen_ash.h
@@ -66,7 +66,8 @@ class ASH_EXPORT ScreenAsh : public gfx::Screen {
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
-  virtual int GetNumDisplays() OVERRIDE;
+  virtual int GetNumDisplays() const OVERRIDE;
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider.cc b/chrome/browser/extensions/api/system_display/display_info_provider.cc
index e01bb72..064688d 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider.cc
+++ b/chrome/browser/extensions/api/system_display/display_info_provider.cc
@@ -4,8 +4,56 @@
 
 #include "chrome/browser/extensions/api/system_display/display_info_provider.h"
 
+#include "base/strings/string_number_conversions.h"
+#include "ui/gfx/display.h"
+#include "ui/gfx/screen.h"
+
 namespace extensions {
 
+namespace {
+
+// Converts Rotation enum to integer.
+int RotationToDegrees(gfx::Display::Rotation rotation) {
+  switch (rotation) {
+    case gfx::Display::ROTATE_0:
+      return 0;
+    case gfx::Display::ROTATE_90:
+      return 90;
+    case gfx::Display::ROTATE_180:
+      return 180;
+    case gfx::Display::ROTATE_270:
+      return 270;
+  }
+  return 0;
+}
+
+// Creates new DisplayUnitInfo struct for |display| and adds it at the end of
+// |list|.
+extensions::api::system_display::DisplayUnitInfo*
+CreateDisplayUnitInfo(const gfx::Display& display,
+               int64 primary_display_id) {
+  extensions::api::system_display::DisplayUnitInfo* unit =
+      new extensions::api::system_display::DisplayUnitInfo();
+  const gfx::Rect& bounds = display.bounds();
+  const gfx::Rect& work_area = display.work_area();
+  unit->id = base::Int64ToString(display.id());
+  unit->is_primary = (display.id() == primary_display_id);
+  unit->is_internal = display.IsInternal();
+  unit->is_enabled = true;
+  unit->rotation = RotationToDegrees(display.rotation());
+  unit->bounds.left = bounds.x();
+  unit->bounds.top = bounds.y();
+  unit->bounds.width = bounds.width();
+  unit->bounds.height = bounds.height();
+  unit->work_area.left = work_area.x();
+  unit->work_area.top = work_area.y();
+  unit->work_area.width = work_area.width();
+  unit->work_area.height = work_area.height();
+  return unit;
+}
+
+}  // namespace
+
 DisplayInfoProvider::DisplayInfoProvider() {
 }
 
@@ -26,6 +74,32 @@ void DisplayInfoProvider::InitializeForTesting(
   provider_.Get() = provider;
 }
 
+void DisplayInfoProvider::RequestInfo(const RequestInfoCallback& callback) {
+  bool success = QueryInfo();
+
+  base::MessageLoopProxy::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, success));
+}
+
+#if !defined(OS_WIN)
+bool DisplayInfoProvider::QueryInfo() {
+  info_.clear();
+
+  // TODO(scottmg): Native is wrong http://crbug.com/133312
+  gfx::Screen* screen = gfx::Screen::GetNativeScreen();
+  int64 primary_id = screen->GetPrimaryDisplay().id();
+  std::vector<gfx::Display> displays = screen->GetAllDisplays();
+  for (int i = 0; i < screen->GetNumDisplays(); ++i) {
+    linked_ptr<extensions::api::system_display::DisplayUnitInfo> unit(
+        CreateDisplayUnitInfo(displays[i], primary_id));
+    UpdateDisplayUnitInfoForPlatform(displays[i], unit.get());
+    info_.push_back(unit);
+  }
+  return true;
+}
+#endif
+
 // static
 DisplayInfoProvider* DisplayInfoProvider::Get() {
   if (provider_.Get().get() == NULL)
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider.h b/chrome/browser/extensions/api/system_display/display_info_provider.h
index ac9c654..65f94eb 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider.h
+++ b/chrome/browser/extensions/api/system_display/display_info_provider.h
@@ -11,6 +11,10 @@
 #include "chrome/browser/extensions/api/system_info/system_info_provider.h"
 #include "chrome/common/extensions/api/system_display.h"
 
+namespace gfx {
+class Display;
+}
+
 namespace extensions {
 
 typedef std::vector<linked_ptr<
@@ -65,6 +69,12 @@ class DisplayInfoProvider : public SystemInfoProvider {
   // The implementation is platform specific.
   virtual bool QueryInfo() OVERRIDE;
 
+  // Update the content of the |unit| obtained for |display| using
+  // platform specific method.
+  void UpdateDisplayUnitInfoForPlatform(
+      const gfx::Display& display,
+      extensions::api::system_display::DisplayUnitInfo* unit);
+
   static base::LazyInstance<scoped_refptr<DisplayInfoProvider> > provider_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayInfoProvider);
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider_chromeos.cc b/chrome/browser/extensions/api/system_display/display_info_provider_chromeos.cc
index 712bc528..dba99e0 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider_chromeos.cc
+++ b/chrome/browser/extensions/api/system_display/display_info_provider_chromeos.cc
@@ -35,21 +35,6 @@ bool IsValidRotationValue(int rotation) {
   return rotation == 0 || rotation == 90 || rotation == 180 || rotation == 270;
 }
 
-// Converts Rotation enum to integer.
-int RotationToDegrees(gfx::Display::Rotation rotation) {
-  switch (rotation) {
-    case gfx::Display::ROTATE_0:
-      return 0;
-    case gfx::Display::ROTATE_90:
-      return 90;
-    case gfx::Display::ROTATE_180:
-      return 180;
-    case gfx::Display::ROTATE_270:
-      return 270;
-  }
-  return 0;
-}
-
 // Converts integer integer value in degrees to Rotation enum value.
 gfx::Display::Rotation DegreesToRotation(int degrees) {
   DCHECK(IsValidRotationValue(degrees));
@@ -67,48 +52,6 @@ gfx::Display::Rotation DegreesToRotation(int degrees) {
   }
 }
 
-// Creates new DisplayUnitInfo struct for |display| and adds it at the end of
-// |list|.
-void AddInfoForDisplay(const gfx::Display& display,
-                       DisplayManager* display_manager,
-                       int64 primary_display_id,
-                       DisplayInfo* list) {
-  linked_ptr<extensions::api::system_display::DisplayUnitInfo> unit(
-      new extensions::api::system_display::DisplayUnitInfo());
-  const gfx::Rect& bounds = display.bounds();
-  const gfx::Rect& work_area = display.work_area();
-  const float dpi = display.device_scale_factor() * kDpi96;
-  const gfx::Insets overscan_insets =
-        display_manager->GetOverscanInsets(display.id());
-
-  unit->id = base::Int64ToString(display.id());
-  unit->name = display_manager->GetDisplayNameForId(display.id());
-  unit->is_primary = (display.id() == primary_display_id);
-  unit->is_internal = display.IsInternal();
-  unit->is_enabled = true;
-  if (display_manager->IsMirrored()) {
-    unit->mirroring_source_id =
-        base::Int64ToString(display_manager->mirrored_display().id());
-  }
-  unit->dpi_x = dpi;
-  unit->dpi_y = dpi;
-  unit->rotation = RotationToDegrees(display.rotation());
-  unit->bounds.left = bounds.x();
-  unit->bounds.top = bounds.y();
-  unit->bounds.width = bounds.width();
-  unit->bounds.height = bounds.height();
-  unit->overscan.left = overscan_insets.left();
-  unit->overscan.top = overscan_insets.top();
-  unit->overscan.right = overscan_insets.right();
-  unit->overscan.bottom = overscan_insets.bottom();
-  unit->work_area.left = work_area.x();
-  unit->work_area.top = work_area.y();
-  unit->work_area.width = work_area.width();
-  unit->work_area.height = work_area.height();
-
-  list->push_back(unit);
-}
-
 // Checks if the given point is over the radius vector described by it's end
 // point |vector|. The point is over a vector if it's on its positive (left)
 // side. The method sees a point on the same line as the vector as being over
@@ -359,7 +302,9 @@ bool SetInfoImpl(const std::string& display_id_str,
   }
 
   int64 display_id = target.id();
-  const gfx::Display& primary = ash::Shell::GetScreen()->GetPrimaryDisplay();
+  // TODO(scottmg): Native is wrong http://crbug.com/133312
+  const gfx::Display& primary =
+      gfx::Screen::GetNativeScreen()->GetPrimaryDisplay();
 
   if (!ValidateParamsForDisplay(info, target, display_manager, primary.id(),
                                 error)) {
@@ -410,14 +355,6 @@ bool SetInfoImpl(const std::string& display_id_str,
 
 }  // namespace
 
-void DisplayInfoProvider::RequestInfo(const RequestInfoCallback& callback) {
-  bool success = QueryInfo();
-
-  base::MessageLoopProxy::current()->PostTask(
-      FROM_HERE,
-      base::Bind(callback, success));
-}
-
 void DisplayInfoProvider::SetInfo(const std::string& display_id,
                                   const DisplayProperties& info,
                                   const SetInfoCallback& callback) {
@@ -428,20 +365,28 @@ void DisplayInfoProvider::SetInfo(const std::string& display_id,
       base::Bind(callback, success, error));
 }
 
-bool DisplayInfoProvider::QueryInfo() {
-  info_.clear();
+void DisplayInfoProvider::UpdateDisplayUnitInfoForPlatform(
+    const gfx::Display& display,
+    extensions::api::system_display::DisplayUnitInfo* unit) {
 
-  DisplayManager* display_manager =
-      ash::Shell::GetInstance()->display_manager();
-  DCHECK(display_manager);
-
-  int64 primary_id = ash::Shell::GetScreen()->GetPrimaryDisplay().id();
-  for (size_t i = 0; i < display_manager->GetNumDisplays(); ++i) {
-    AddInfoForDisplay(display_manager->GetDisplayAt(i), display_manager,
-                      primary_id, &info_);
+  ash::internal::DisplayManager* display_manager
+      = ash::Shell::GetInstance()->display_manager();
+  unit->name = display_manager->GetDisplayNameForId(display.id());
+  if (display_manager->IsMirrored()) {
+    unit->mirroring_source_id =
+        base::Int64ToString(display_manager->mirrored_display().id());
   }
 
-  return true;
+  const float dpi = display.device_scale_factor() * kDpi96;
+  unit->dpi_x = dpi;
+  unit->dpi_y = dpi;
+
+  const gfx::Insets overscan_insets =
+      display_manager->GetOverscanInsets(display.id());
+  unit->overscan.left = overscan_insets.left();
+  unit->overscan.top = overscan_insets.top();
+  unit->overscan.right = overscan_insets.right();
+  unit->overscan.bottom = overscan_insets.bottom();
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider_mac.cc b/chrome/browser/extensions/api/system_display/display_info_provider_mac.cc
index 2b22e1e..3776bf9 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider_mac.cc
+++ b/chrome/browser/extensions/api/system_display/display_info_provider_mac.cc
@@ -6,11 +6,6 @@
 
 namespace extensions {
 
-void DisplayInfoProvider::RequestInfo(const RequestInfoCallback& callback) {
-  // Redirect the request to a worker pool thread.
-  StartQueryInfo(callback);
-}
-
 void DisplayInfoProvider::SetInfo(
     const std::string& display_id,
     const api::system_display::DisplayProperties& info,
@@ -20,9 +15,10 @@ void DisplayInfoProvider::SetInfo(
       base::Bind(callback, false, "Not implemented"));
 }
 
-// TODO(hongbo): implement display info querying on Mac OS X.
-bool DisplayInfoProvider::QueryInfo() {
-  return false;
+void DisplayInfoProvider::UpdateDisplayUnitInfoForPlatform(
+    const gfx::Display& display,
+    extensions::api::system_display::DisplayUnitInfo* unit) {
+  NOTIMPLEMENTED();
 }
 
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider_win.cc b/chrome/browser/extensions/api/system_display/display_info_provider_win.cc
index 9d21278..846d777 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider_win.cc
+++ b/chrome/browser/extensions/api/system_display/display_info_provider_win.cc
@@ -67,11 +67,6 @@ BOOL CALLBACK EnumMonitorCallback(HMONITOR monitor,
 
 }  // namespace
 
-void DisplayInfoProvider::RequestInfo(const RequestInfoCallback& callback) {
-  // Redirect the request to a worker pool thread.
-  StartQueryInfo(callback);
-}
-
 void DisplayInfoProvider::SetInfo(
     const std::string& display_id,
     const api::system_display::DisplayProperties& info,
@@ -81,6 +76,7 @@ void DisplayInfoProvider::SetInfo(
       base::Bind(callback, false, "Not implemented"));
 }
 
+// TODO(hongbo): consolidate implementation using gfx::Display/gfx::Screen.
 bool DisplayInfoProvider::QueryInfo() {
   info_.clear();
 
@@ -90,4 +86,10 @@ bool DisplayInfoProvider::QueryInfo() {
   return false;
 }
 
+void DisplayInfoProvider::UpdateDisplayUnitInfoForPlatform(
+    const gfx::Display& display,
+    extensions::api::system_display::DisplayUnitInfo* unit) {
+  NOTIMPLEMENTED();
+}
+
 }  // namespace extensions
diff --git a/chrome/browser/extensions/api/system_display/display_info_provider_x11.cc b/chrome/browser/extensions/api/system_display/display_info_provider_x11.cc
index adfdb14..3776bf9 100644
--- a/chrome/browser/extensions/api/system_display/display_info_provider_x11.cc
+++ b/chrome/browser/extensions/api/system_display/display_info_provider_x11.cc
@@ -6,11 +6,6 @@
 
 namespace extensions {
 
-void DisplayInfoProvider::RequestInfo(const RequestInfoCallback& callback) {
-  // Redirect the request to a worker pool thread.
-  StartQueryInfo(callback);
-}
-
 void DisplayInfoProvider::SetInfo(
     const std::string& display_id,
     const api::system_display::DisplayProperties& info,
@@ -20,9 +15,10 @@ void DisplayInfoProvider::SetInfo(
       base::Bind(callback, false, "Not implemented"));
 }
 
-// TODO(hongbo): implement X11 display info querying.
-bool DisplayInfoProvider::QueryInfo() {
-  return false;
+void DisplayInfoProvider::UpdateDisplayUnitInfoForPlatform(
+    const gfx::Display& display,
+    extensions::api::system_display::DisplayUnitInfo* unit) {
+  NOTIMPLEMENTED();
 }
 
 }  // namespace extensions
diff --git a/ui/aura/test/test_screen.cc b/ui/aura/test/test_screen.cc
index 13d1232..474ac29 100644
--- a/ui/aura/test/test_screen.cc
+++ b/ui/aura/test/test_screen.cc
@@ -113,10 +113,14 @@ gfx::NativeWindow TestScreen::GetWindowAtCursorScreenPoint() {
   return root_window_->GetTopWindowContainingPoint(point);
 }
 
-int TestScreen::GetNumDisplays() {
+int TestScreen::GetNumDisplays() const {
   return 1;
 }
 
+std::vector<gfx::Display> TestScreen::GetAllDisplays() const {
+  return std::vector<gfx::Display>(1, display_);
+}
+
 gfx::Display TestScreen::GetDisplayNearestWindow(
     gfx::NativeWindow window) const {
   return display_;
diff --git a/ui/aura/test/test_screen.h b/ui/aura/test/test_screen.h
index c4615c7..00d684b 100644
--- a/ui/aura/test/test_screen.h
+++ b/ui/aura/test/test_screen.h
@@ -48,7 +48,8 @@ class TestScreen : public gfx::Screen,
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
-  virtual int GetNumDisplays() OVERRIDE;
+  virtual int GetNumDisplays() const OVERRIDE;
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
diff --git a/ui/gfx/screen.h b/ui/gfx/screen.h
index 9410d02..7958f65 100644
--- a/ui/gfx/screen.h
+++ b/ui/gfx/screen.h
@@ -5,6 +5,8 @@
 #ifndef UI_GFX_SCREEN_H_
 #define UI_GFX_SCREEN_H_
 
+#include <vector>
+
 #include "base/basictypes.h"
 #include "ui/base/ui_export.h"
 #include "ui/gfx/display.h"
@@ -55,7 +57,10 @@ class UI_EXPORT Screen {
   // Returns the number of displays.
   // Mirrored displays are excluded; this method is intended to return the
   // number of distinct, usable displays.
-  virtual int GetNumDisplays() = 0;
+  virtual int GetNumDisplays() const = 0;
+
+  // Returns the list of displays that are currently available.
+  virtual std::vector<gfx::Display> GetAllDisplays() const = 0;
 
   // Returns the display nearest the specified window.
   virtual gfx::Display GetDisplayNearestWindow(NativeView view) const = 0;
diff --git a/ui/gfx/screen_android.cc b/ui/gfx/screen_android.cc
index 6c4d633..1376136 100644
--- a/ui/gfx/screen_android.cc
+++ b/ui/gfx/screen_android.cc
@@ -50,7 +50,11 @@ class ScreenAndroid : public Screen {
     return GetPrimaryDisplay();
   }
 
-  virtual int GetNumDisplays() OVERRIDE { return 1; }
+  virtual int GetNumDisplays() const OVERRIDE { return 1; }
+
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE {
+    return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+  }
 
   virtual gfx::Display GetDisplayMatching(
       const gfx::Rect& match_rect) const OVERRIDE {
diff --git a/ui/gfx/screen_gtk.cc b/ui/gfx/screen_gtk.cc
index 8ef803d..85dd87e 100644
--- a/ui/gfx/screen_gtk.cc
+++ b/ui/gfx/screen_gtk.cc
@@ -107,13 +107,18 @@ class ScreenGtk : public gfx::Screen {
   // Returns the number of displays.
   // Mirrored displays are excluded; this method is intended to return the
   // number of distinct, usable displays.
-  virtual int GetNumDisplays() OVERRIDE {
+  virtual int GetNumDisplays() const OVERRIDE {
     // This query is kinda bogus for Linux -- do we want number of X screens?
     // The number of monitors Xinerama has?  We'll just use whatever GDK uses.
     GdkScreen* screen = gdk_screen_get_default();
     return gdk_screen_get_n_monitors(screen);
   }
 
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+  }
+
   // Returns the display nearest the specified window.
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE {
diff --git a/ui/gfx/screen_ios.mm b/ui/gfx/screen_ios.mm
index dfb0d1b..6450e14 100644
--- a/ui/gfx/screen_ios.mm
+++ b/ui/gfx/screen_ios.mm
@@ -26,7 +26,7 @@ class ScreenIos : public gfx::Screen {
     return gfx::NativeWindow();
   }
 
-  virtual int GetNumDisplays() OVERRIDE {
+  virtual int GetNumDisplays() const OVERRIDE {
 #if TARGET_IPHONE_SIMULATOR
     // UIScreen does not reliably return correct results on the simulator.
     return 1;
@@ -35,6 +35,11 @@ class ScreenIos : public gfx::Screen {
 #endif
   }
 
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+  }
+
   // Returns the display nearest the specified window.
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE {
diff --git a/ui/gfx/screen_mac.mm b/ui/gfx/screen_mac.mm
index d9e1f0a..8f85ae6 100644
--- a/ui/gfx/screen_mac.mm
+++ b/ui/gfx/screen_mac.mm
@@ -89,7 +89,7 @@ class ScreenMac : public gfx::Screen {
     return gfx::NativeWindow();
   }
 
-  virtual int GetNumDisplays() OVERRIDE {
+  virtual int GetNumDisplays() const OVERRIDE {
     // Don't just return the number of online displays.  It includes displays
     // that mirror other displays, which are not desired in the count.  It's
     // tempting to use the count returned by CGGetActiveDisplayList, but active
@@ -123,6 +123,11 @@ class ScreenMac : public gfx::Screen {
     return display_count;
   }
 
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE {
+    NOTIMPLEMENTED();
+    return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+  }
+
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView view) const OVERRIDE {
     NSWindow* window = [view window];
diff --git a/ui/gfx/screen_win.cc b/ui/gfx/screen_win.cc
index 8bb1548..23dbc9d 100644
--- a/ui/gfx/screen_win.cc
+++ b/ui/gfx/screen_win.cc
@@ -55,10 +55,15 @@ gfx::NativeWindow ScreenWin::GetWindowAtCursorScreenPoint() {
   return GetNativeWindowFromHWND(window_hwnd);
 }
 
-int ScreenWin::GetNumDisplays() {
+int ScreenWin::GetNumDisplays() const {
   return GetSystemMetrics(SM_CMONITORS);
 }
 
+std::vector<gfx::Display> ScreenWin::GetAllDisplays() const {
+  NOTIMPLEMENTED();
+  return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+}
+
 gfx::Display ScreenWin::GetDisplayNearestWindow(gfx::NativeView window) const {
   HWND window_hwnd = GetHWNDFromNativeView(window);
   if (!window_hwnd) {
diff --git a/ui/gfx/screen_win.h b/ui/gfx/screen_win.h
index f6b7d40a..cc59352 100644
--- a/ui/gfx/screen_win.h
+++ b/ui/gfx/screen_win.h
@@ -21,7 +21,8 @@ class UI_EXPORT ScreenWin : public gfx::Screen {
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
-  virtual int GetNumDisplays() OVERRIDE;
+  virtual int GetNumDisplays() const OVERRIDE;
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView window) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.cc b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
index 77dbaa4..a462da7 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_x11.cc
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.cc
@@ -39,7 +39,8 @@ class DesktopScreenX11 : public gfx::Screen {
   virtual bool IsDIPEnabled() OVERRIDE;
   virtual gfx::Point GetCursorScreenPoint() OVERRIDE;
   virtual gfx::NativeWindow GetWindowAtCursorScreenPoint() OVERRIDE;
-  virtual int GetNumDisplays() OVERRIDE;
+  virtual int GetNumDisplays() const OVERRIDE;
+  virtual std::vector<gfx::Display> GetAllDisplays() const OVERRIDE;
   virtual gfx::Display GetDisplayNearestWindow(
       gfx::NativeView window) const OVERRIDE;
   virtual gfx::Display GetDisplayNearestPoint(
@@ -95,12 +96,17 @@ gfx::NativeWindow DesktopScreenX11::GetWindowAtCursorScreenPoint() {
   return NULL;
 }
 
-int DesktopScreenX11::GetNumDisplays() {
+int DesktopScreenX11::GetNumDisplays() const {
   // TODO(erg): Figure this out with oshima or piman because I have no clue
   // about the XRandR implications here.
   return 1;
 }
 
+std::vector<gfx::Display> DesktopScreenX11::GetAllDisplays() const {
+  // TODO(erg): Do the right thing once we know what that is.
+  return std::vector<gfx::Display>(1, GetPrimaryDisplay());
+}
+
 gfx::Display DesktopScreenX11::GetDisplayNearestWindow(
     gfx::NativeView window) const {
   // TODO(erg): Do the right thing once we know what that is.